The present disclosure relates to information security techniques, and more specifically, to preventing visual exposure of security information.
Entering private information at public situations through input devices such as a keyboard may cause information leakage. A typical scenario is that, with the wide use of portable digital devices, such as smart phones, tablet computers and the like, users may handle their transactions at any time and at any places, including handling transactions in public situations. A user may need to enter private information in a dialog box displayed on a portable digital device in a public situation, and a peeper may find out the content inputted by the user through observation.
For example, if content inputted by a user is displayed on a portable digital device, a peeper may observe the display of the portable digital device to find out the content inputted by the user. Correspondingly, special characters such as “*” and the like instead of content inputted by the user can be displayed on the display of the portable digital device. This method can prevent a peeper from finding out the content inputted by the user by peeping through the display of the portable digital device. However, the peeper still can recognize the content inputted by the user by observing which keys the user clicked on an input device such as a keyboard. In particular, for a keyboard with fixed key positions, user inputs on the keyboard can be inferred through observing finger actions when the user is inputting. A keyboard with varied key positions can solve the above problem. However, if a peeper can further observe key positions on the keyboard, he/she may still find out content inputted by the user. In the case of a virtualized keyboard on a touch screen, an anti-peeping membrane can be provided on the touch screen, so that keys on the virtualized keyboard can be observed only in a certain visual angle range. However, this method is unsuitable for physical keyboards.
Other private information input manners, such as using hardware certificates, biometric features, and dynamic password generators need additional hardware overheads.